1. Field of the Invention
This invention relates to a water softener of the type wherein hard water is passed through ion exchange resin or mineral beads to remove hardness ions from the water. The ion exchange resin, to a limited extent, also removes dissolved iron, by the ion exchange process, and oxidized iron by filtration. The ion exchange resin or mineral beads are recharged to restore their hardness and iron removal capability by passing brine through the resin or mineral beads and by backwashing.
2. Description of Related Art Including Information Disclosed under Secs. 1.97-1.99
In the past it has been the commonly accepted practice to use in a water softener resin beads having a mesh size within a predetermined limited range. Resin beads falling within the sizes of 16 to 40 mesh are considered a "standard mesh" for residential water softeners. Resin beads falling within the sizes of 40 to 50 mesh are considered a "fine mesh" for residential water softeners. As implied by the designation, "standard mesh" is the more commonly used resin size. Fine mesh resin is preferable from the point of view of it being more efficiently regenerated by brine, and for more readily removing dissolve iron and oxidized iron from hard water. The applicants are unaware of any teaching, whether it be a patent or other publication which teaches or suggests the use of resin beads of a combination of different ranges of meshes.
A search for U.S. patents did not uncover any teaching or suggestion of the applicant's invention. The following U.S. Pat. Nos. reveal water processing systems utilizing a mixture of cation and anion exchange resins:
______________________________________ U.S. Pat. No. INVENTOR ISSUE DATE ______________________________________ 4,120,786 Petersen et al 10/17/78 4,472,282 Crits 09/18/84 4,564,455 Flynn et al 01/14/86 ______________________________________